code: def _noparen(variable):
      "remove enclosing parenthesis for a single-variable expression"
      if variable.startswith("(") and variable.endswith(")"):
          return variable[1:-1]
      return variable
  
imports: from numpy import ndarray, asarray, any
  from mystic._symbolic import solve
  from mystic.tools import list_or_tuple_or_ndarray, flatten
label_desc: Use image node_id 9 for calling a global function with example usage: _noparen(variable) and returns: variable, variable